class Things:
    pass

class Inanimate(Things):
    pass
class Sidewalks(Inanimate):
    pass

class Animate(Things):
    pass

class Aminals(Animate):
    def breathe(self):
        print("breathing")
        return
    def move(self):
        print ("moving!")
        return
    def eat(self):
        return

class Mammals(Aminals):
    def feed(self):
        print("feeding young with milk")
        return

class Graffes(Mammals):
    legs=0
    def __init__(self,spots):
       self.graffe_spots=spots;    #初始化定义类的属性，def 里面只能用self.name

    def eat(self):
        print("eating")
        return

g = Graffes(100)
g.eat()
g.feed()
a = g.legs
print("%s" %(g.graffe_spots))
